Fitting for this Halloween season, Suburbicon is a Frankenstein’s monster of a movie, stitching together an old Coen brothers screenplay from 1986 with a modern social-message script penned by George Clooney, who also signed on to direct. The result lumbers across the screen, occasionally frightening, sometimes hilarious, but never one thing for long enough to be consistently enjoyable.

The setting is Suburbicon, a white-bread suburb at the tail end of the 1950s. An advertisement for the subdivision tells us it was founded just after the war as a “melting pot of diversity,” which in this case means white folk from all corners of America.

One of its perfect nuclear families is the Lodges, Rosie and Gardner, and their 12-year-old son, Nicky. The latter is played by Noah Jupe, the former by Julianne Moore and Matt Damon. And to make things interesting, Moore also plays her own twin sister, Margaret.

Once the story gets moving, the less you know the better. So let’s just say the plot is sparked to life when thugs break into the Lodges’ lodge and engage in violence and robbery that Gardner does very little to stop – although fans of the Coen brothers will know that the first splash of aggression is seldom the last. I can also reveal that, much later, you will realize that you’ve never seen a peanut-butter and jam sandwich laced with such, um, portent.

Isaac.Hilary Bronwyn Gayle/Paramount Pictures via AP

The work of the criminals (Glenn Fleshler, Alex Hassell) captures the notice of the local police chief (Jack Conley), Nicky’s gruff uncle Mitch (Gary Basaraba) and a dogged insurance investigator, played by Oscar Isaac. With the exception of Isaac, none of these secondary characters are Coen regulars, but they all have that ragged, worn-in look that epitomizes the brothers’ cherry-picked casts. The film’s ’50s décor is also superb.

Isaac is the best thing in the film, which is often the case for this inexplicably not-Academy-nominated performer. (His name is Oscar, for heaven’s sake!) But as good as this story is, it betrays its 30-year-old provenance; there are themes here that the Coens have since explored more adeptly, not least in 1996’s Fargo.

Meanwhile, Clooney’s half of the screenplay is weaker still, exploring what happens when a black family (Leith M. Burke and Karimah Westbrook) with its own young son (Tony Espinosa) moves into the neighbourhood. The historical template is William and Daisy Myers, who in 1957 became the first black residents in the all-white Philadelphia suburb of Levittown, and suffered greatly for it.

It’s a fascinating and ugly moment in American race relations, but in this telling, Mr. and Mrs. Meyers do little more than silently forbear – literally in his case, for he has no lines at all. And while the two families in the movie share a backyard fence over which the kids play catch, there’s otherwise little to connect them.

Ultimately, Suburbicon might have been better split into two movies, with each one given the space it needed to breathe. And isn’t that what the suburbs promised?